Schneider Super Angulon 65mm F8 lens for Graflexgreenspun.com : LUSENET : Large format photography : One Thread
I acquired a Schneider Super Angulon 65mm F8 lens for my Crown Graphic. There is severe vignetting on the ground glass for which the seller of the lens has informed me that I need a recessed lensboard.
Is anyone familiar with this? A recessed lensboard for the Graflex? When focused at infinite, the rear element is already <1" from the ground glass.
Thanks for any help.
-- Robert Hollander (email@example.com), July 05, 2000
If the lens is focusing, then you don't need a recessed lens board. A recessed board is used to get the back of a short focal lenght lens closer to the film plane. It won't help with vignetting. This lens just covers 4x5, so what you are seeing could be normal. As you know, vignetting will improve as you stop down. Take a sample shot with the film you intend to use. If it's still bad, then you need a center filer.
-- sheldon hambrick (firstname.lastname@example.org), July 05, 2000.
A recessed board is needed only if the lens won't focus to infinity at minimum extension.
_All_ WA lenses show fairly severe falloff when looking at a groundglass, especially if a fresnel isn't used; part of this is real falloff in coverage/brightness, while most of it is simply scatter. Actual falloff is reduced upon stopping down; the 65 f8 barely covers 4x5, so there still may be quite a bit.
To brighten up your view, you need to install a fresnel lens behind the groundglass. That should help, but won't entirely eliminate the visual falloff, which just goes with the territory.
-- John Hicks (email@example.com), July 05, 2000.
The f/8 version of the Super Angulon is marginal on 4x5 at the very best. Wide open, the lens only covers an image circle of 133mm. This is far short of the 153mm diagonal of 4x5 film at infinity.
At the working aperture of f/22, this lens only covers 155mm, a scant 2mm more than the film diagonal. This means zero movements. To use this lens on 4x5, you *must* operate it at f/22 or you will vignette. If you have filters, etc in place, they will most likely vignette even more, depending upon the filter.
-- Bruce Gavin (firstname.lastname@example.org), July 10, 2000.